Correct me if I am wrong but they are full of direct damage red cards? Well anyway, list the pros and cons.
Well, what are you talking about? Sligh or just Stupid Red Burn? There's a difference. There's a primer that covers decks that fall into the the Burn/Sligh category. If you read it, you'll understand the decks and you'll become a better player to boot.
Decks with nothing but direct damage can hit certain decks hard because they're so narrow, but in general, they easily run out of steam and are reduced to topdecking.
Creatures don't go to the graveyard that quickly.